Process of making indoxyl, &amp;c.



UNITED STATES PATENT OFFICE.

MARTIN MUGDAN AND WILLY HERRMANN, 0F NUREMBERG, GERMANY, ASSIGNORS TOTHE FIRM OF CONSORTIUM FUR ELEK'IROCHEMISGHE INDUSTRIE, GESELL- SOHAFTMIT BESCHRKNKTEB HAFTUNG, 0F NUREMBERG, GERMANY.

PROCESS OF MAKING INDOXYL, 850.

No Drawing.

Patented June 7, 1910.

To all whom it may concern:

Be it known that we, MARTIN Muoosn, doctor of philosophy, chemist, andlVmLY Hnnnnsxn, doctor of philosophy, chemist, subjects of the King ofPrussia, Gerin nn Emperor, residing at 54 Gugelstrasso, huremberg,Kingdom of Bavaria, German Empire, have jointly invented new and uscfuiImprovements in Processes of Manufacturing Indoxvl and DerivativesThereof, of which the following is a specification.

This invention relates to a process for the production of indoxyl andderivatives thereof from aryl-glycin bodies. It is already known thatphenylglycin and its derivatives and homologucs, on being heated withalkali hydroxides can he com-cried into indoxyl, or its derivatives, orhomologues, and that indigo may be obtained from the indoxyl thusobtained by oxidation for instance by blowing air into the aqueoussolution of the melt. The yield of indigo in this case, however, is verybad. We have found that indoxyl and derivatives thereof can be obtainedfrom aryi'glycin bodies by heating these compounds with alloys ofsilicon and metals of the alkaline earths in the presence of anhydrouscaustic alkalics. The process yields good results and is easily carriedout, as the alloys of silicon and metals of the alkaline earths arereadily and cheaply obtained.

The following are examples showing how the invention is performed butthe invention is not limited to these.

Example I: Into an anhydrous melt of 280 parts by weight of causticpotash and of 200 parts by weight of caustic soda, are slowly introducedat about 2-50 centigi'ade, 50 parts by weight of pulverizedcalciumsilicon (containing about 30 )e1' cent. calcium). Thecalcium-silicon a loy dissolves while a brisk evolution of hydrogentakes place. WVhile the melt is kept well stirred, 50 parts by weight offinely pulverized phenylglycin potassium are introduced at a temperatureof 220 ccntigrade. The temperature is then raised to about 250centigrade and the reaction is interrupted when blowing air through asample dissolved in water the amount of the dye formed no longerincreases. The melt is dissolved in 10000 parts by weight of water at100 ccnti rade, and the solution thus obtained \vhici contains theindoxyl, is filtered off from any insoluble substances produced. If itbe desired to obtain the indoxyl in the solid state, the solution isevaporated to dryness in the presence of an inert gas such as hydrogen.As the indoxyl is generally prepared for the purpose of obtainingindigo, its isolation may be omitted and the indigo prepared directly byintroducing air into the solution. The indigo dye thus obtained is ofgreat purity.

In carrying out the process the quantitative proportions andtemperatures may be varied. I It has been found advantageous tointroduce the alloy of silicon and alkaline earth metal intimately mixedwith the arylglycin body into the melt. of caustic alkalies.

Example II: Into an anhydrous melt of 300 parts by weight of causticsoda and 500 parts by weight of caustic potash is slowly introducedwhile stirring, at a temperature of about 220 centigrade, an intimatemixture of 200 parts by weight of phenylglycinpotassium and 130 parts ofcalcium-silicon (containing about 30 per cent. of calcium). Thetcn'iperature is then raised to 250 centigradc and the process carriedout as described in Example I.

In the above examples the calcium-silicon can be replaced by alloys ofsilicon with other metals of the alkaline earths, for instancebarium-silicon may be made.

Instead of phenylglycimpotassium other compounds of l'ihcnylglycin canbe used, for instance phenylglycin-sodiuni, phenyiglycinamid orphenylglycin-anilid.

If it be desired to produce homologues of indoxyl homologucs ofplicuylglycin are used. From tolyl-glychnpotassimu CH,.G l-L NI-I.CI-lCOOK methyl indoxyl is obtained.

We claim:

1. A process for producing indoxyl and derivatives thermf by heating anaryl-glycili body with an alloy of silicon and a metal of 100 7 '2. Apmcess dmusicausticz- 'ulkahes.

I improduuing indnxyl and derivatives thereof by int-rodu'cin a mixture7 Q5 of an alloy of silicon and u meta of the a1- kaline earths and ofan uryllycin body into -mglted anhydrous caustic .a kulies.

liqulkaline ngrth in the presence of unhy In testimony whereof we uflixour signatures in presence of two witnesses.

MARTIN MUGDAN. WILLY I'IERRMANN. Witnesses:

ERICK I'IOEFER, ADAM KIBGHEA.

